Substrate for semiconductor device, semiconductor chip mounting substrate, semiconductor device and method of fabrication thereof, and circuit board, together with electronic equipment

ABSTRACT

A substrate for semiconductor device which is formed of a material that can be cut into separate pieces and has mounting regions for a plurality of semiconductor chips, and at least one hole is formed therein at a position of intersection between a plurality of cutting lines for cutting the substrate into a plurality of individual products.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a substrate for a semiconductordevice, a semiconductor chip mounting substrate, a semiconductor deviceand method of fabrication thereof, and a circuit board, together withelectronic equipment.

[0003] 2. Description of Related Art

[0004] Methods have been developed for providing small packages such aschip scale/size packages (CSPs), which involve mounting a plurality ofsemiconductor chips on a flexible substrate then sealing the entireassembly in resin. The resultant sealed product is then cut intoindividual packages.

[0005] If the flexible substrate is cut by a blade or router in thiscase, a problem occurs in that the cutting generates dust at the cornerportions of individual products, so a better solution is required.

SUMMARY OF THE INVENTION

[0006] To solve this problem, the present invention provides a substratefor a semiconductor device, a semiconductor chip mounting substrate, asemiconductor device and method of fabrication thereof, and a circuitboard, together with electronic equipment comprising the same, whereinthe generation of cutting dust is reduced.

[0007] (1) According to a first aspect of the present invention, thereis provided a substrate for a semiconductor device, having a mountingregion for a semiconductor chip, wherein at least one hole is formed ata position where cutting lines intersect.

[0008] The substrate for a semiconductor device in accordance with thisinvention can be cut apart to separate it into individual products thatare semiconductor devices. The cutting is done along cutting lines. Inpractice, the cutting lines are of a striped form having a certainwidth. Corner portions of individual products are formed at positionswhere the cutting lines intersect with this aspect of the invention,“hole” is not limited to a through hole; it can also refer to any othertype of hole that does not penetrate, such as a depression. If a hole isformed at each position where cutting lines intersect, part of thesubstrate for the semiconductor device forms an indented shape at eachcorner portion of each individual product. If a depression is formed ateach position where cutting lines intersect, part of the substrate forthe semiconductor device is made thinner at each corner portion of eachindividual product.

[0009] Since parts of the substrate for the semiconductor device areeither indented inward or is thinner at the corner portions of theindividual products, it is therefore possible to reduce the amount ofcutting dust when the cutting is done.

[0010] (2) In this substrate for a semiconductor device, one of theholes may be formed at the position where the cutting lines intersect;and the hole may be formed to a size that comprises an intersectionportion of the cutting lines.

[0011] This ensures that the corner portions of individual products aredefined by inner wall surfaces of the holes or thinner portions formedby the provision of the depressions. Part of the substrate for thesemiconductor device is formed to be indented inward or thinner at eachcorner portion of each individual product.

[0012] (3) In this substrate for a semiconductor device, a plurality ofthe holes may be formed at the position where the cutting linesintersect; and part of each of the holes may be superimposed on anintersection portion between the cutting lines.

[0013] This ensures that the corner portions of individual products aredefined by inner wall surfaces of the holes or thinner portions formedby the provision of the depressions. Part of the substrate for thesemiconductor device can be formed to be indented inward or thinner ateach corner portion of each individual product.

[0014] Moreover, since it is sufficient that part of each hole issuperimposed on the intersection portion between the cutting lines, eachhole can be made smaller.

[0015] (4) In this substrate for a semiconductor device, the pluralityof holes may be positioned on edges of one of the cutting lines that isto be cut last, in the intersection portion.

[0016] (5) In this substrate for a semiconductor device, the pluralityof holes may be formed on part of the cutting line that is to be cutlast, when that part is to be cut earlier than the intersection portionbetween the cutting lines.

[0017] (6) In this substrate for a semiconductor device, the pluralityof holes may be formed on part of the cutting line that is to be cutlast, when that part is to be cut after the intersection portion betweenthe cutting lines.

[0018] (7) In this substrate for a semiconductor device, the spacingbetween one of the holes formed on an edge of the cutting line that isto be cut last and another of the holes formed on another edge of thecutting line may be less than the thickness of a cutting portion of acutting tool.

[0019] This configuration ensures that the cutting can be done to cutaway a part of each hole and that the corner portions of individualproducts can be defined by inner wall surfaces of the holes or thinnerportions formed by provision of the depressions.

[0020] (8) In this substrate for a semiconductor device, at least one ofthe holes may be formed; and the hole may have an aperture portion thatis closed by a cover.

[0021] This makes it possible to prevent the sealing resin from flowinginto the hole, and thus prevent the sealing resin from seeping from onesurface of the semiconductor device to the other surface thereof throughthe hole.

[0022] (9) In this substrate for a semiconductor device, aninterconnecting pattern may be formed; and the cover may be formed ofthe same material as the interconnecting pattern.

[0023] This makes it possible to form the cover without increasing thesteps of the fabrication process.

[0024] (10) According to a second aspect of the present invention, thereis provided a semiconductor chip mounting substrate, comprising: asubstrate of a material that can be cut into separate pieces, in whichis formed at least one hole at an intersection portion between cuttinglines for separating the substrate into a plurality of individualproducts; and a plurality of semiconductor chips which are mounted onthe substrate.

[0025] The substrate in accordance with this aspect of the invention, onwhich is mounted a plurality of semiconductor chips, can be cut apart toform a plurality of individual products. The cutting is done along thecutting lines. In practice, the cutting lines are of a striped formhaving a certain width. Corner portions of individual products of thesubstrate are formed at positions where the cutting lines intersect.

[0026] With this aspect of the invention, “hole” is not limited to athrough hole; it can also refer to any other type of hole that does notpenetrate, such as a depression. If a hole is formed at each positionwhere cutting lines intersect, each corner portion of each individualproduct of the substrate forms an indented shape. If a depression isformed at each position where cutting lines intersect, each cornerportion of each individual product of the substrate is made thinner.

[0027] Since the corner portions of individual pieces of the substrateare either indented inward or are thinner, it is possible to reduce theamount of cutting dust even when the cutting is done along theintersecting cutting lines.

[0028] (11) In this semiconductor chip mounting substrate, the pluralityof semiconductor chips may be sealed in by resin.

[0029] This configuration makes it possible to cut the resin apartsimultaneously with the cutting of the substrate.

[0030] (12) In this semiconductor chip mounting substrate, the resin mayfill the hole.

[0031] This provides resin in the intersection portion between cuttinglines. If holes are formed in the substrate, each corner portion of theindividual pieces of substrate and resin is formed by resin. Ifdepressions are formed in the substrate, each corner portion of theindividual pieces of substrate and resin is formed by a thinner piece ofsubstrate and the resin.

[0032] (13) In this semiconductor chip mounting substrate, the hole maybe formed to a size that comprises the intersection portion of thecutting lines.

[0033] (14) In this semiconductor chip mounting substrate, the hole mayhave an aperture portion that is closed by a cover, and the resin may beprovided over a surface of the substrate for a semiconductor devicewhere the cover is provided.

[0034] This makes it possible to prevent the resin from flowing into thehole and thus prevent seepage of the resin from one surface of thesubstrate to the other surface thereof through the hole.

[0035] (15) According to a third aspect of the present invention, thereis provided a semiconductor device comprising:

[0036] a semiconductor chip;

[0037] a substrate on which the semiconductor chip is mounted and whichis formed by cutting apart a larger substrate; and

[0038] resin for sealing the semiconductor chip;

[0039] wherein the semiconductor device has an outer shape having acorner portion; and

[0040] wherein apart of the substrate is indented further inward than anedge surface of the resin at the corner portion.

[0041] This aspect of the invention provides a configuration thatreduces the amount of cutting dust that remains on the substrate afterbeing generated at the corner portions by the cutting apart of thesubstrate.

[0042] (16) In this semiconductor device, the substrate at the cornerportion may form a shape that is indented in the opposite direction fromthe direction in which the corner portion protrudes, and thus an edgesurface of the substrate may be indented further inward than the edgesurface of the resin.

[0043] (17) In this semiconductor device, the formation of a thinnerportion in the substrate at the corner portion may ensure that a surfaceof the thinner portion of the substrate is indented further inward thanthe edge surface of the resin.

[0044] (18) In this semiconductor device, the part of the substrate thatis indented further inward than the edge portion of the resin at thecorner portion may be covered by the resin.

[0045] This ensures that part of the substrate is covered by resin atthe corner portion so that no cutting dust is generated by the cuttingapart of the substrate.

[0046] (19) In this semiconductor device, a cover may be provided at thecorner portion, between the substrate and the resin; and the part of thesubstrate that is indented further inward than the edge surface of theresin may be exposed.

[0047] (20) According to a fourth aspect of the present invention, thereis provided a circuit board which has any of the previously describedsemiconductor devices mounted thereon.

[0048] (21) According to a fifth aspect of the present invention, thereis provided electronic equipment which is provided with any of thepreviously described semiconductor devices.

[0049] (22) According to a sixth aspect of the present invention, thereis provided a method of fabricating a semiconductor device, the methodcomprising:

[0050] a first step of mounting a plurality of semiconductor chips on asubstrate on which is formed at least one hole at a position wherecutting lines intersect, then sealing the plurality of semiconductorchips with resin; and

[0051] a second step of cutting the substrate and the resin intoindividual products along the cutting lines, through at least part ofthe hole.

[0052] With this aspect of the invention, the substrate on which aplurality of semiconductor chips is mounted is cut apart to form aplurality of individual products. The cutting is done along cuttinglines. In practice, the cutting lines are of a striped form having acertain width. Corner portions of individual pieces of the substrate andresin are formed at positions where the cutting lines intersect.

[0053] With this aspect of the invention, “hole” is not limited to athrough hole; it can also refer to any other type of hole that does notpenetrate, such as a depression. If a hole is formed at each positionwhere cutting lines intersect, part of the substrate for thesemiconductor device forms an indented shape at each corner portion ofeach individual piece of the substrate and resin. If a depression isformed at each position where cutting lines intersect, part of thesubstrate for the semiconductor device is made thinner at each cornerportion of each individual piece of the substrate and resin.

[0054] Since the part of the substrate is either indented inward or isthinner at each corner portion of each individual piece of the substrateand resin, it is possible to reduce the amount of cutting dust when thecutting is done along the intersecting cutting lines.

[0055] (23) In this method of fabricating a semiconductor device, theresin may fill the hole in the first step.

[0056] This ensures that resin is provided at the each intersectionportion of the cutting lines. If holes are formed in the substrate, eachcorner portion of the individual pieces of the substrate and resin isformed by resin. If depressions are formed in the substrate, each cornerportion of the individual pieces of the substrate and resin is formed bya thinner piece of the substrate and resin.

[0057] (24) In this method of fabricating a semiconductor device, atleast one of the holes may be formed in the substrate; a cover may beprovided to block the hole, before the first step; and flow of the resininto the hole during the first step may be prevented by the cover.

[0058] This makes it possible to prevent the resin from flowing into thehole and thus prevent seepage of the resin from one surface of thesubstrate to the other surface thereof through the hole.

[0059] (25) The method of fabricating a semiconductor device may furthercomprise a step of forming an interconnecting pattern in the substrate,before the first step, and the cover may be formed during the step offorming the interconnecting pattern.

[0060] This makes it possible to provide a cover without increasing thenumber of fabrication steps.

[0061] (26) In this method of fabricating a semiconductor device, one ofthe holes may be formed at the position where the cutting linesintersect; and the substrate and the resin may be cut through an innerside of the hole in the second step.

[0062] This makes it possible to define the corner portions ofindividual pieces of the substrate with inner wall surfaces of the holesor thinner portions formed by the provision of the depressions.

[0063] (27) In this method of fabricating a semiconductor device, aplurality of the holes may be formed at the position where the cuttinglines intersect; the plurality of holes may be formed to be positionedon edges of one of the cutting lines that is to be cut last, at theposition where the cutting lines intersect; and the substrate and theresin may be cut through part of the respective holes in the secondstep.

[0064] This makes it possible to define the corner portions ofindividual products of the substrate with inner wall surfaces of theholes or thinner portions formed by the provision of the depressions.Moreover, since it is sufficient that part of each hole is superimposedon the intersection portion between the cutting lines, each hole can bemade smaller.

[0065] (28) In this method of fabricating a semiconductor device, thesubstrate and the resin may be cut by a cutting tool having a thicknessthat is greater than the spacing between one of the holes formed on anedge of the cutting line that is to be cut last and another of the holesformed on another edge of the cutting line.

[0066] This configuration ensures that the cutting is done to cut awaypart of each hole and that the corner portions of individual products ofthe substrate are defined with inner wall surfaces of the holes orthinner portions formed by provision of the depressions.

BRIEF DESCRIPTION OF THE DRAWINGS

[0067]FIG. 1 shows a substrate for a semiconductor device in accordancewith a first embodiment to which this invention is applied;

[0068]FIG. 2 shows a method of fabricating a semiconductor device inaccordance with the first embodiment to which this invention is applied;

[0069]FIG. 3 shows more the method of fabricating a semiconductor devicein accordance with the first embodiment to which this invention isapplied;

[0070]FIGS. 4A and 4B show still more of the method of fabricating asemiconductor device in accordance with the first embodiment to whichthis invention is applied;

[0071]FIG. 5 shows even more of the method of fabricating asemiconductor device in accordance with the first embodiment to whichthis invention is applied;

[0072]FIG. 6 shows yet more of the method of fabricating a semiconductordevice in accordance with the first embodiment to which this inventionis applied;

[0073]FIG. 7 shows a semiconductor device in accordance with the firstembodiment to which this invention is applied;

[0074]FIG. 8 is another view of the semiconductor device in accordancewith the first embodiment to which this invention is applied;

[0075]FIG. 9 shows a substrate for a semiconductor device in accordancewith a second embodiment to which this invention is applied;

[0076]FIG. 10 shows a method of fabricating a semiconductor device inaccordance with the second embodiment to which this invention isapplied;

[0077]FIGS. 11A and 11B show a modification of the substrate for asemiconductor device in accordance with the second embodiment to whichthis invention is applied;

[0078]FIG. 12 shows a semiconductor device in accordance with a thirdembodiment to which this invention is applied;

[0079]FIG. 13 shows a semiconductor device in accordance with a fourthembodiment to which this invention is applied; and

[0080]FIG. 14 shows electronic equipment that is provided with asemiconductor device fabricated by applying the method in accordancewith this invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0081] Embodiments of the present invention are described below withreference to the accompanying drawings.

[0082] First Embodiment

[0083] A substrate for a semiconductor device in accordance with a firstembodiment to which this invention is applied is shown in FIG. 1. Aftera plurality of semiconductor chips 20 has been mounted on a substratefor a semiconductor device (hereinafter called “substrate”) 10, as shownin FIG. 2, the assembly is cut into a plurality of individual productsto form a plurality of semiconductor devices 30 (see FIG. 8). Thesubstrate 10 becomes an interposer for the semiconductor devices whenthey are separated.

[0084] The substrate 10 is formed from a material that can be cut intoseparate pieces. The present invention is particularly effective whencorner portions are formed by the cutting, and when the substrate 10 hasbeen formed of a material that readily generates cutting dust at thosecorner portions. It is preferable to apply the present invention whenthe substrate 10 is formed of a material that is elastic, by way ofexample. The material of the substrate 10 could be any of variousinorganic materials or materials including inorganic substance, but itis preferable to use an organic material therefor. An example of thesubstrate 10 formed from an organic material is a flexible substrateconsisting of a polyimide resin.

[0085] At least one mounting region 12 is provided on the substrate 10,for mounting the plurality of semiconductor chips 20 (a plurality ofmounting regions 12 is shown in FIG. 1, but it could equally well beone). An interconnecting pattern 13 (see FIG. 8) could also be formed inat least one surface of each mounting region 12 (in most cases, only onesurface is used therefor, but both surfaces could also be used). Aplurality of through holes 14 could be formed in the substrate 10, toenable electrical contact between one surface and the other surface. Theplurality of through holes 14 could be formed in each mounting region12. Inner wall surfaces of the through holes 14 could be plated with aconductive material such as copper or gold, or the through holes 14could be filled with a conductive material. A component such as a solderball to form an external terminal could be formed on top of each of thethrough holes 14.

[0086] At least one hole 16 is formed in the substrate 10, separate fromthe through holes 14. More specifically, at least one hole 16 is formedat each position where cutting lines L intersect (there is only one holefor each intersection in FIG. 1). The shape of this hole 16 is notlimited; it could be a round hole or a square hole. The size of the hole16 (its diameter if it is a round hole) is greater than the width of thecutting lines L, in other words, the thickness of the blade of a cuttingtool. If the thickness of the blade of the cutting tool is 100 μm to 300μm (generally 100 μm to 200 μm, but preferably on the order of 150 μm),by way of example, it is preferable that the diameter of the hole 16 is150 μm to 500 μm, taking into account positioning errors of the cuttinglines L of 50 μm to 200 μm.

[0087] The cutting lines L indicate positions where the substrate 10 isto be severed and are set at positions that delimit the plurality ofindividual products to be obtained from the substrate 10. In the exampleshown in FIG. 1, the plurality of cutting lines L is divided into afirst group consisting of a plurality of parallel cutting lines L and asecond group of a plurality of cutting lines L that extend perpendicularto the cutting lines L of the first group.

[0088] Since the cutting lines L indicate regions of the substrate 10that will be separated while being cut at a predetermined width, theyform stripes of a predetermined width in practice. The cutting lines Lhave a width that is the thickness of the blade of the cutting tool.Therefore, each intersection portion 18 between the cutting lines L isactually a region having a predetermined area, not a point.

[0089] Each hole 16 is formed to a size that comprises the correspondingintersection portion 18 between a plurality of cutting lines L therein,in other words, is formed to be larger than the intersection portion 18.If each intersection portion 18 is positioned completely within thecorresponding hole 16, the corner portions of individual pieces of thesubstrate 10 are not defined by the intersection portions 18. The cornerportions of each individual piece of the substrate 10 are defined by theinner wall surfaces of the corresponding holes 16. When the substrate 10is cut into a plurality of individual products, therefore, no cuttingdust is generated at the corner portions of the individual products.

[0090] With this embodiment of the invention, the peripheral edgeportions of the substrate 10 are cut away, then the plurality ofindividual products is formed from the interior region. If it does notmatter whether cutting dust is generated at the peripheral edge portionsthat are to be discarded, part of each relevant intersection portion 18could protrude from the corresponding hole 16 in the direction of thatperipheral edge portion. In such a case, the corner portions of theindividual pieces of the substrate 10 are defined by the inner wallsurfaces of the holes 16, as described above, but the corner portions ofthe peripheral edge portions that are to be discarded are formed byintersecting cut and thus it is inevitable that cutting dust will begenerated.

[0091] The substrate for a semiconductor device in accordance with thisembodiment has the above configuration and a semiconductor device usingthis substrate is fabricated by the method described below. The methodof fabricating a semiconductor device comprises a semiconductor chipmounting substrate fabrication process (first step) and a semiconductorchip mounting substrate cutting process (second step).

[0092] Semiconductor Chip Mounting Substrate Fabrication Process

[0093] The process of fabricating the semiconductor chip mountingsubstrate is shown in FIGS. 2 to 4A. A plurality of semiconductor chips20 will be mounted on the substrate 10, each in one of the plurality ofmounting regions 12, as shown in FIG. 2. In this embodiment of theinvention, the semiconductor chips 20 will be bonded so that theterminals thereof turn upward (face-up bonding). The semiconductor chips20 could be bonded to the substrate 10 by an adhesive 21 or the like.The interconnecting pattern 13 (see FIG. 8) is formed on the substrate10. The semiconductor chips 20 could be mounted on the surface on whichthe interconnecting pattern 13 is formed, and a plurality of externalterminals 26 could be formed on the surface on the opposite side, viathe through holes 14, by a process that will be described later.

[0094] The semiconductor chips 20 and the interconnecting pattern 13 arethen connected electrically. In FIG. 3, they are shown connectedtogether by wires 22, by way of example. Alternatively, thesemiconductor chips 20 could be mounted on the substrate 10 by face-downbonding, in contrast to the orientation of this embodiment. In such acase, the electrical connections could be done by using an anisotropicconductive material, solder, conductive paste, or the like, orultrasonic waves could be used to apply a metal bond. Heat or pressurecould be added to the ultrasonic waves.

[0095] The plurality of semiconductor chips 20 is then sealed in withresin 24 (by batch sealing, for example), as shown in FIG. 4A. Theentire substrate 10 could be sealed in by the resin 24. A metal diecould be used for this sealing, in which case the resin 24 could becalled molding resin. Alternatively, the resin 24 could be provided ontop of the substrate 10 then spread evenly by a squeegee, or by potting.The surface of the resin 24 provided on top of the substrate 10 could beeither flat or uneven. In a variant shown in FIG. 4B by way of example,grooves 126 could be formed in resin 124. If the grooves 126 are formedalong the cutting lines L, this would facilitate the positioning for thecutting.

[0096] If the interconnecting pattern 13 is formed on the surface of thesubstrate 10 on which the semiconductor chips 20 are mounted, theinterconnecting pattern 13 is covered and protected by the resin 24. Theresin 24 could also fill all the holes 16 formed in the substrate 10.

[0097] The semiconductor chip mounting substrate shown in FIG. 4A isobtained by the above steps. The semiconductor chip mounting substrateis an intermediate product in the fabrication of a plurality ofsemiconductor devices, with the plurality of semiconductor chips 20incorporated therein. The plurality of semiconductor chips 20 are sealedin by the resin 24. Details of the substrate 10 of the semiconductorchip mounting substrate are as described previously. The holes 16 of thesubstrate 10 could be filled with the resin 24.

[0098] Before the semiconductor chip mounting substrate is cut apart, aplurality of external terminals 26 could be provided thereon, as shownin FIG. 5. At this point, it is possible to provide the externalterminals 26 simultaneously for a plurality of semiconductor devices.The external terminals 26 could be solder balls. The external terminals26 could be provided on land portions formed on the substrate 10. If theinterconnecting pattern 13 is formed on the surface on which the resin24 is provided, electrical connection between the external terminals 26and the interconnecting pattern 13 can be obtained either by solder orother conductive material that is provided within the through holes 14or by the through holes 14 having inner surfaces plated with copper orother conductive material.

[0099] Semiconductor Chip Mounting Substrate Cutting Process

[0100] The semiconductor chip mounting substrate comprising thesubstrate 10, the plurality of semiconductor chips 20, and the resin 24is then cut into separate products, as shown in FIG. 6. A cutting toolsuch as a blade 28 that is used for slicing silicon wafers could be usedfor this cutting into separate products. The cutting tool, such as theblade 28, is moved relative to the substrate 10 to cut apart thesubstrate 10. Either the blade 28 could be moved or the substrate 10could be moved. The positions of the cutting is on the cutting lines Lshown in FIG. 1. In other words, the substrate 10 and the resin 24 arecut apart through the inner sides of the holes 16, to obtainsemiconductor devices 30 that are individual products. If the resin 24has filled the holes 16, corner portions 32 are formed for eachsemiconductor device 30 by the resin 24 (see FIG. 7). There is thereforeno generation of cutting dust from the substrate 10.

[0101] A cross section of the substrate 10 and the resin 24 is shown inFIG. 7. In the example shown in FIG. 7, part of the substrate 10 isindented further inward than the edge surface of the resin 24 at thecorner portion 32 of the semiconductor device 30. As mentionedpreviously, each intersection portion 18 between cutting lines L ispositioned within one of the holes 16 of the substrate 10, so that thecorner portions of the substrate 10 are defined by inner wall surfacesof the holes 16. The inner wall surface of each of the holes 16 of thesubstrate 10 therefore forms a shape that is indented in the oppositedirection to the direction in which the corner portion 32 protrudes, atthe corner portion 32 of each semiconductor device 30. Since the resin24 fills the holes 16 in the substrate 10 during the process offabricating the semiconductor chip mounting substrate, the inner wallsurfaces of the holes 16 are covered with the resin 24.

[0102] The semiconductor device 30 in accordance with this embodiment ofthe invention is shown in FIG. 8. This semiconductor device 30 comprisesthe semiconductor chip 20, an individual piece of the substrate 10 onwhich the semiconductor chip 20 was mounted and which was formed bycutting a larger substrate apart, and an individual piece of the resin24 which seals the semiconductor chip 20 and which was formed by cuttinga larger piece of resin apart. All other characteristics of thisembodiment are as previously described.

[0103] The semiconductor device 30 of FIG. 8 is mounted on a circuitboard 34. In general, this circuit board 34 would have an organicsubstrate, such as a glass epoxy substrate by way of example. Aninterconnecting pattern 36 is then formed on the circuit board 34 of amaterial such as copper, to create desired circuitry, and this wiringpattern 36 and the external terminals 26 of the semiconductor device 30are connected together to make them electrically conductive.

[0104] Second Embodiment

[0105] A substrate for a semiconductor device in accordance with asecond embodiment to which this invention is applied is shown in FIG. 9.A plurality of holes 46 is formed in a substrate for a semiconductordevice (hereinafter called “substrate”) 40, as shown in FIG. 9. Thesubstrate 40 could have the same configuration as the substrate 10 ofFIG. 1, apart from the holes 16.

[0106] In this embodiment of the invention a plurality of holes 46 areformed at positions where the pluralities of cutting lines L₁ and L₂intersect. The cutting lines L₁ and the cutting lines L₂ intersect atright angles. The cutting lines L₁ and L₂ are the same as the cuttinglines L of the first embodiment. Therefore, the cutting lines L₁ and L₂form stripes of a predetermined width, as shown in FIG. 10. Part of therespective hole 46 overlap an intersection portion 48 between thecutting lines L₁ and L₂.

[0107] In this embodiment of the invention, a plurality of the holes 46is formed to be positioned on the edges of the cutting line L₁ or thecutting line L₂. In addition, corner portions of the intersectionportions 48 of the cutting lines L₁ and L₂ overlap the correspondingholes 46.

[0108] The spacing D between each pair of the holes 46 that arepositioned on the edges of the cutting lines L₁ or L₂ is preferably lessthan the width of the cutting lines L₁ and L₂, in other words, less thanthe thickness of the cutting tool (for example, the blade 28), as shownin the enlargement of FIG. 9. If the thickness of the blade of thecutting tool is 100 μm to 300 μm (generally 100 μm to 200 μm, butpreferably on the order of 150 μm), by way of example, the spacing D ispreferably less than that. The diameter of the holes 46 is sufficient toallow for positioning error in the cutting lines L₁ and L₂, that is onthe order of 50 μm to 200 μm, for example. With this embodiment of theinvention, the diameter of the holes 46 can be made smaller than in thefirst embodiment. As a result, it is possible to reduce a state in whichthe resin incorporated into the holes 46 is forced out onto the surfaceof the substrate 40.

[0109] With this embodiment of the invention, the cutting of theplurality of intersecting cutting lines L₁ and L₂ is done first alongthe cutting lines L₁, and subsequently (finally) along the cutting linesL₂. The cutting that is done last generates cutting dust at the cornerportions of individual parts of the substrate 40, so it is preferablethat the hole 146 of FIG. 10 is positioned at at least a corner portionof an individual product. When the plurality of individual products isto be formed from all other regions excluding the peripheral edgeportions of the substrate 40, it is not always necessary to have holes246, 346, and 466 that are positioned at the corner portions within theexcluded peripheral edge portions.

[0110] Similarly, the holes 46 are sufficient to be positioned on theedges of the cutting line L₂ for the final cutting, when the cornerportions of a plurality of individual products are to be formed by theplurality of intersecting cutting lines L₁ and L₂.

[0111] A modification of this embodiment of the invention is shown inFIGS. 11A and 11B, with the cutting being performed along the cuttingline L₂ from the top of each diagram to the bottom.

[0112] If cutting dust is to be generated at part of the cutting line L₂that is cut by the final cutting and that part is cut earlier than theintersection portion 48, the holes 46 are formed as shown in FIG. 11A.In other words, the holes 46 could be formed on the cutting line L₂ onlyat the part that is cut earlier than the intersection portion 48. Inthat case, it is originally difficult for cutting dust to occur atanother part of the cutting line L₂ that is cut after the intersectionportion 48.

[0113] Alternatively, if cutting dust is to be generated at part of thecutting line L₂ that is cut by the final cutting and that part is cutafter the intersection portion 48, the holes 46 are formed as shown inFIG. 11B. In other words, the holes 46 could be formed on the cuttingline L₂ only at the part that is cut after the intersection portion 48.In that case, it is originally difficult for cutting dust to occur atanother part of the cutting line L₂ that is cut earlier than theintersection portion 48.

[0114] The conditions that determine on which part of the cutting linecutting dust is most likely to occur depend on the properties of thesubstrate 40 and the resin and the cutting method (such as the directionof rotation or direction of movement of the cutting tool and the surfaceof the substrate 40 that is touched by the cutting tool).

[0115] This embodiment of the invention has the configuration describedabove and details that were described with reference to the firstembodiment can also be applied as far as possible thereto. In addition,details that were described with reference to the first embodiment canalso be applied to a semiconductor chip mounting substrate that uses thesubstrate 40 in accordance with this embodiment of the invention,allowing for differences in the configuration of the substrate 40.

[0116] The method of fabricating a semiconductor device that uses thesubstrate 40 in accordance with this embodiment of the inventioninvolves cutting the substrate 40 and the resin through part of each ofthe holes 46. A cutting tool that is thicker than the spacing D betweeneach pair of holes 46 is used during the cutting step to cut through thesubstrate 40 and the resin. All other details that were described withreference to the first embodiment can be applied to this embodiment.

[0117] Third Embodiment

[0118] A semiconductor device in accordance with a third embodiment towhich this invention is applied is shown in FIG. 12. The semiconductordevice of FIG. 12 comprises a substrate 50 that has formed individualproducts and resin 52 that seals a plurality of semiconductor chips thatwere mounted on the substrate 50. A thinner portion 56 is formed in thesubstrate 50 at each of corner portions 54 of the semiconductor device.The thinner portion 56 is formed as a depression in at least one of theupper and lower surfaces of the substrate 50. The thickness of thethinner portion 56 is preferably between approximately ⅓ and ¼ of thethickness of the substrate 50, by way of example. The size of thethinner portion 56 (or the diameter thereof, if circular) is preferablygreater than the thickness of the cutting tool (when viewed from adirection perpendicular to the substrate 50). If the depression isplaced facing into the resin 52, as shown in FIG. 12, the resin 52 couldcover that depression. Alternatively, the depression could be on theopposite side from the resin 52. The formation of the thinner portion 56ensures that the depression of the substrate 50 is indented furtherinward than the edge surfaces of the resin 52.

[0119] The individual pieces of the substrate 50 that are used by thesemiconductor devices in accordance with this embodiment can be formedfrom substrates for semiconductor devices having mounting regions for aplurality of semiconductor chips. More specifically, the holes 16 or 46of the substrate 10 or 40 of the first or second embodiment could beconverted into depressions to give a structure that can be used as asubstrate for semiconductor devices. In that case, the depressions arecut to form the previously described thinner portions 56.

[0120] Since depressions are formed instead of holes in the substratefor a semiconductor device in accordance with this embodiment of theinvention, there is no seepage of resin to the opposite side when resinis provided. This substrate for a semiconductor device could be used tofabrication a semiconductor chip mounting substrate. Semiconductordevices could be fabricated by cutting apart this semiconductor chipmounting substrate. The methods described above with reference to theprevious embodiments can be applied thereto. Since the cutting is donethrough the depressions instead of holes, the cutting ends at portionsthat have become thinner, so there is little cutting dust.

[0121] Chemical half-etching could be used when forming the depressionsof this substrate for semiconductor devices. In such a case, thedepressions could be formed on either the surface provided with theresin or on the opposite side thereto. Alternatively, a substrate for asemiconductor device could be used to fabricate a conductor chipmounting substrate, then depressions are formed in a substrate for asemiconductor device that forms one part thereof. In such a case, thedepressions are formed on the opposite side from the surface on whichthe resin has already been provided.

[0122] Fourth Embodiment

[0123] A semiconductor device in accordance with a fourth embodiment ofthis invention will now be described, with reference to FIG. 13. Thesemiconductor device in accordance with this embodiment has theconfiguration of the semiconductor device described with reference tothe first or second embodiment, but with the addition of a cover (orseal member, or shielding member) 66.

[0124] In other words, the cover 66 is provided between a substrate 60and resin 62 at each corner portion 64 of the semiconductor device. Anedge surface 68 that is formed to be indented in the opposite directionto the direction of protrusion of the corner portion 64 is exposed atthe corner portion 64. The edge surface 68 is indented further inwardthan the edge surfaces of the resin 62. Note that a material such as aresin could be provided to cover the edge surface 68.

[0125] The semiconductor device in accordance with this embodiment ofthe invention could be configured by using a substrate for asemiconductor device wherein the aperture portion of each of the holes16 or 46 of the substrate 10 or 40 of the first or second embodimentcould be closed off by the cover 66. The material of the cover 66 couldbe a resin or a metal such as copper. The cover 66 could be formed ofthe same material as the interconnecting pattern (a conductive materialsuch as copper), at the same time that the interconnecting pattern isformed on the substrate for the semiconductor device. If the cover 66 ismade at the same time as the interconnecting pattern, there is no needto increase the number of fabrication steps. Alternatively, the cover 66could be provided on the surface on the opposite side from theinterconnecting pattern. Further alternatively, a liquid coatingmaterial could be poured into the holes 16 or 46 then solidified. Noteif that the color of the cover 66 is different from the color of thesubstrate for the semiconductor device, the color of the cover 66 willbe visible through the holes 16 or 46. In other words, the holes 16 or46 can be identified by the color of the cover 66. Since the holes 16 or46 are aligned along the cutting lines L, L₁, and L₂, this can be usedto mark the cutting.

[0126] If the substrate for a semiconductor device in accordance withthis embodiment is used and resin is provided over the surface on whichthe covers 66 are provided, the resin will not flow from the holes 16 or46 and thus there will be no seepage to the opposite side.

[0127] All other details that were described with reference to the firstand second embodiments can be applied to this embodiment.

[0128] A notebook-sized personal computer 100 having a semiconductordevice to which this invention is applied is shown in FIG. 14.

[0129] Note that the “semiconductor chip” that is a structural componentof the present invention could be replaced by an “electronic element,”and electronic elements (either active elements or passive elements) canbe mounted on a substrate to fabricate an electronic component, in amanner similar to that of semiconductor chips. Examples of electroniccomponents fabricated by using such electronic elements include opticalelements, resistors, capacitors, coils, oscillators, filters,temperature sensors, thermistors, varistors, variable resistors, orfuses, by way of example.

1-21. (Canceled)
 22. A method of fabricating a semiconductor device, themethod comprising: mounting a plurality of semiconductor chips on asubstrate on which is formed at least one hole at a position wherecutting lines intersect, then sealing the plurality of semiconductorchips with resin; and cutting the substrate and the resin intoindividual products along the cutting lines through at least part of thehole.
 23. The method of fabricating a semiconductor device as defined inclaim 22, the resin filling the hole in mounting the plurality ofsemiconductor chips.
 24. The method of fabricating a semiconductordevice as defined in claim 22, at least one of the holes being formed inthe substrate, a cover being provided to block the hole, before themounting the plurality of semiconductor chips, and flow of the resininto the hole during mounting the plurality of semiconductor chips beingprevented by the cover.
 25. The method of fabricating a semiconductordevice as defined in claim 24, further comprising forming aninterconnecting pattern in the substrate, before mounting the pluralityof semiconductor chips, the cover being formed during forming theinterconnecting pattern.
 26. The method of fabricating a semiconductordevice as defined in claim 22, one of the holes being formed at theposition where the cutting lines intersect, and the substrate and theresin being cut through an inner side of the hole in cutting thesubstrate and the resin.
 27. The method of fabricating a semiconductordevice as defined in claim 22, a plurality of the holes being formed atthe position where the cutting lines intersect, the plurality of holesbeing positioned on edges of one of the cutting lines that is to be cutlast, at the position where the cutting lines intersect, and thesubstrate and the resin being cut through part of each of the holescutting the substrate and the resin.
 28. The method of fabricating asemiconductor device as defined in claim 27, the substrate and the resinbeing cut by a cutting tool having a thickness that is greater than thespacing between one of the holes formed on an edge of the cutting linethat is to be cut last and another of the holes formed on another edgeof the cutting line.